Semiconductor device and method for manufacturing same

ABSTRACT

A semiconductor device is provided having a high performance resistance element. In an N-type well isolated by an insulating film, two higher concentration N-type regions are formed. An interlayer insulating film is also formed. In a plurality of openings in the interlayer insulating film, one electrode group having a plurality of electrodes is formed on one N-type region, while a second electrode group having a plurality of electrodes is formed on the other N-type region. The relationship between the two N-type regions is between an island region and an annular region surrounding the island. The annular region of the N-type well between the island region and the annular region serves as a resistor R. Thus, discharge channels for charges applied excessively because of ESD or the like evenly exist in the periphery (four regions) of the one N-type region.

RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2004-109162 filed Apr. 1, 2004 which is hereby expressly incorporated byreference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a semiconductor device used in asemiconductor integrated circuit and having a protective resistanceelement, and a method for manufacturing the same.

2. Related Art

The smaller the size of input-output transistors become because oftrends toward microminiaturization of semiconductor integrated circuits,the more easily the breakdown of gate oxide films due to electrostaticdischarge (ESD) is caused. One of anti-electrostatic measures is toprovide an input-output protective device upstream of input-outputtransistors. For example, the input-output protective device includes aparasitic bipolar transistor, and dissipates a current by bipolaroperation to protect input-output transistors when an excess voltagesuch as ESD is transmitted from pads (for example, refer to JapaneseUnexamined Patent Publication No. 2001-36006 (p. 3-4, FIG. 1)).

In some input-output transistors having a certain size or structure, theprovision of an input-output protective device is not required and aresistance element, which is inexpensive, contributes to electrostaticprotection. Even in a structure including an input-output protectivedevice, it is important to provide a resistance element between pads andthe input-output protective device, or upstream of input-outputtransistors, for inducing an adequate voltage drop. Typical one ofvarious configurations of these resistance elements is a diffusedresistor (well resistor). At present, such a diffused resistor does nothave a preferable structure since anti-electrostatic measures areinsufficient, and therefore there is a room for improvement.

Resistance elements made up of the above diffused resistor (wellresistor) are formed simultaneously with a forming step of othertransistor elements or the like. Therefore, the impurity concentrationof the resistance elements is not adjusted independently in general.Thus the resistance value is adjusted with the length and width of adiffused region between coupled wires. This sometimes makes it difficultto form a desired resistance element within a limited region. Also,since discharge channel is along a single direction, charges appliedexcessively because of ESD or the like may damage resistors.

The present invention is made in consideration of the abovecircumstances, and is intended to provide a semiconductor device havingan inexpensive and high performance resistance element that can ensure,within a more reduced area, a large area for discharging excess chargesdue to ESD or the like. The present invention is also intended toprovide a method for manufacturing the semiconductor device.

SUMMARY

A semiconductor device according to the present invention comprises: asemiconductor base of a first conductivity type; a first conductivecoupling region of the first conductivity type provided on thesemiconductor base; a second conductive coupling region of the firstconductivity type provided on the semiconductor base so as to surroundthe first conductive coupling region; a first electrode group having aplurality of electrodes that is provided on the first conductivecoupling region; and a second electrode group having a plurality ofelectrodes that is provided on the second conductive coupling region.

A semiconductor device according to the present invention comprises: asemiconductor base of a first conductivity type; a first insulating filmprovided on the semiconductor base; a first conductive coupling regionof the first conductivity type in a center part and a second conductivecoupling region of the first conductivity type surrounding the firstconductive coupling region, the first and second conductive couplingregions being isolated from each other by the first insulating film; asecond insulating film provided on the first conductive coupling regionand the second conductive coupling region; a first electrode grouphaving a plurality of electrodes that is provided on the firstconductive coupling region via a plurality of openings in the secondinsulating film; a second electrode group having a plurality ofelectrodes that is provided on the second conductive coupling region viaa plurality of openings in the second insulating film; a first wiringpattern coupled to a plurality of predetermined electrodes of the firstelectrode group; and a second wiring pattern coupled to a plurality ofpredetermined electrodes of the second electrode group.

According to the semiconductor device of the present invention, therelationship between the first conductive coupling region and the secondconductive coupling region is one between an island region and anannular region surrounding the island. The annular region between theisland region and the annular region serves as a resistor. Thus,discharge channels for charges applied excessively because of ESD or thelike evenly exist in the periphery (four regions) of the firstconductive coupling region.

Also, a silicide metal layer is preferably formed in the firstconductive coupling region and the second conductive coupling regionexcept for a predetermined region adjacent to the first insulating film.That is, for a layer having a silicide metal layer on the surfacethereof, regions free of a silicide metal layer are preferably formed inend (edge) parts of regions serving as the resistor in order to avoidthe concentration of charges.

In the semiconductor device according to the present invention, thesemiconductor base is one well region provided on a semiconductorsubstrate, and the semiconductor base between the first conductivecoupling region and the second conductive coupling region functions as aresistor. The resistor can be formed simultaneously with a step offorming other elements, which provides advantages in manufacturingefficiency and manufacturing costs.

In addition, in the semiconductor device according to the presentinvention, the semiconductor base has a pattern that is at leastfourfold symmetric about a center of the first conductive couplingregion, and the semiconductor base between the first conductive couplingregion and the second conductive coupling region functions as aresistor. The resistor can be formed simultaneously with a step offorming other elements, which provides advantages in manufacturingefficiency and manufacturing costs. In addition, a resistance element inwhich a pattern is fourfold symmetric about the first electrode groupcan be formed. This allows greater flexibility in the coupling structureof the second electrode group.

In the semiconductor device according to the present invention, aperipheral electrode of the first electrode group in a predeterminednumber is arranged closest to an edge of the first conductive couplingregion in four regions, and an electrode of the second electrode groupin a predetermined number is arranged in four regions so as to face theperipheral electrode of the first electrode group.

Furthermore, in the semiconductor device according to the presentinvention, the first electrode group is distributed in a whole regionfrom a center of the first conductive coupling region to a predeterminedregion. A peripheral electrode of the first electrode group in apredetermined number is arranged closest to an edge of the firstconductive coupling region in four regions, and an electrode of thesecond electrode group in a predetermined number is arranged in fourregions so as to face at least the peripheral electrode of the firstelectrode group in a predetermined number.

Also, in the semiconductor device according to the present invention,the first conductive coupling region has a planar shape obtained byremoving four corner parts from a quadrangle and having at least foursides. The first electrode group is prepared so that an electrode in apredetermined number is arranged along the four sides, and an electrodeof the second electrode group in a predetermined number is arranged soas to face at least the electrode of the first electrode group in apredetermined number.

According to the semiconductor device of the present invention, bothends of a resistor are made up of one-to-one correspondences between apredetermined number of electrodes and therefore regions preferentiallyserving as a resistor are established. This allows a structure that iseasier to be designed as a resistance element. Here, it is alsoimportant that a distance between the first conductive coupling regionand the second conductive coupling region in a region in which the firstelectrode group faces the second electrode group is smaller than adistance between the first conductive coupling region and the secondconductive coupling region in other regions.

A method for manufacturing a semiconductor device according to thepresent invention comprises: forming an annular first insulating film ona semiconductor base; forming, with using the first insulating film as amask, a first conductive coupling region of a first conductivity type ina center part of the semiconductor base and a second conductive couplingregion of the first conductivity type in a periphery of the firstconductive coupling region; forming a second insulating film on thefirst conductive coupling region and the second conductive couplingregion; and forming a first electrode group and a second electrode groupthat have a plurality of electrodes on the first conductive couplingregion and the second conductive coupling region, respectively, via aplurality of openings in the second insulating film.

According to the method for manufacturing a semiconductor device of thepresent invention, the first conductive coupling region and the secondconductive coupling region are formed as an island region and an annularregion surrounding the island. The annular region between the islandregion and the annular region serves as a resistor. By forming the firstelectrode group and the second electrode group that have a plurality ofelectrodes, charges that have been excessively applied because of ESD orthe like can be discharged toward the periphery (four directions) of thefirst conductive coupling region evenly.

The method for manufacturing a semiconductor device preferably furthercomprises forming a first wiring pattern coupled to a plurality ofpredetermined electrodes of the first electrode group and a secondwiring pattern coupled to a plurality of predetermined electrodes of thesecond electrode group.

In the method for manufacturing a semiconductor device according to thepresent invention, the semiconductor base is one well region provided ona semiconductor substrate, and forms a resistor, between the firstconductive coupling region and the second conductive coupling region,that is at least fourfold symmetric about a center of the firstconductive coupling region. Thus, a resistance element that is fourfoldsymmetric about the first electrode group can be formed. This allowsgreater flexibility in the coupling pattern of the second electrodegroup.

In the method for manufacturing a semiconductor device according to thepresent invention, an inner circumference of the first insulating filmhas an octagon shape that has at least longitudinal four sides, and anouter circumference forms regions of four sides facing the four sides. Awidth between the inner and outer circumferences in the regions of foursides is smaller than a width between the inner and outer circumferencesin four corner regions. A structure in which designing of wiring and aresistance element is facilitated is achieved.

In the method for manufacturing a semiconductor device according to thepresent invention further comprises, prior to the step of forming thesecond insulating film: forming a protective layer for preventingsilicidation that covers a predetermined region, of the first conductivecoupling region and the second conductive coupling region, adjacent toat least the first insulating film; and forming a silicide metal layeron the first conductive coupling region and the second conductivecoupling region except for the predetermined region. That is, end (edge)parts of regions serving as a resistor require a protective layer forpreventing silicidation in order to avoid the concentration of charges.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an essential part of a semiconductordevice according to a first embodiment.

FIG. 2 is a sectional view along line F2-F2 in FIG. 1.

FIG. 3 is a plan view showing a structure including a wiring pattern inaddition to the structure of FIG. 1.

FIGS. 4A and 4B are circuit diagrams including a resistance element forprotection in an input-output system around an IC chip.

FIGS. 5A and 5B are plan views showing structures of modificationsrelated to the first embodiment.

FIG. 6 is a plan view showing an essential part of a semiconductordevice according to a second embodiment.

FIG. 7 is a sectional view along line F7-F7 in FIG. 6.

DETAILED DESCRIPTION

FIG. 1 is a plan view showing an essential part of a semiconductordevice according to a first embodiment of the present invention. FIG. 2is a sectional view along line F2-F2 in FIG. 2.

An insulating film 11 for isolation is formed on an N-type semiconductorbase, for example, an N-type well 10, on a semiconductor substrate. Inthe N-type well 10 isolated by the insulating film 11 for isolation,N-type regions 12 and 13 into which an N-type impurity of higherconcentration is further introduced are formed. That is, the N-typeregion 12 is formed at the center part and the N-type region 13surrounds the N-type region 12. An interlayer insulating film 14 isformed. In a plurality of openings in the interlayer insulating film 14,an electrode group G1 having a plurality of electrodes 15 is formed onthe N-type region 12, while an electrode group G2 having a plurality ofelectrodes 16 is formed on the N-type region 13. In other words, theN-type regions 12 and 13 serve as conductive coupling regions at bothends of a resistance region made of the N-type well 10. Ideally, thedevice has a fourfold symmetric pattern about the center of the N-typeregion 12, and the N-type well 10 between the N-type regions 12 and 13serve as a resistor.

The insulating film 11 for isolation makes the N-type region 12 have aplanar shape that is obtained by removing four corners from a quadrangleand has at least four sides. In the drawing, the shape of the N-typeregion 12 approximates an octagon shape having longitudinal four sides.The insulating film 11 for isolation also makes the shape of the N-typeregion 13 approximate an octagon shape in which both inner and outercircumferences have longitudinal four sides. Opposite distance D1between the four sides of the N-type regions 12 and 13 is, at largest,smaller than opposite distance D2 between the sides of the N-typeregions 12 and 13 at four corner regions.

The electrode group G1 is distributed in the whole region from thecenter of the N-type region 12 to a predetermined region. Peripheralelectrodes of the electrodes 15 are arranged in a predetermined number(six in this embodiment) in four regions and are closest to the edges ofthe N-type region 12. A predetermined number (six in this embodiment) ofthe electrodes 16 of the electrode group G2 are arranged in four regionsso as to face the peripheral electrodes 15 of the electrode group G1.The way of arranging the electrodes 16 is not limited to this embodimentin which the electrodes 16 are arranged in one row of a predeterminednumber (six) in each of four regions. The electrodes 16 may be arrangedin a plurality of rows of a predetermined number (six).

A method for manufacturing a resistance element shown as a structure inFIGS. 1 and 2 is as follows. The insulating film 11 for isolation thatis at least annular is formed on the N-type well 10. The insulating film11 for isolation is formed so that the inner circumference thereof hasan octagon shape having at least longitudinal four sides while the outercircumference thereof has four sides facing the four sides of the innercircumference. The width of the region between the four sides is setsmaller than that at four corner regions (D1<D2).

Subsequently, an N-type impurity is ion-implanted into the center andperipheral parts of the N-type well 10 with using the insulating film 11for isolation as a mask, to form the N-type regions 12 and 13. The kindand concentration of the ion depends on N-type regions of othersemiconductor elements (not shown) that are formed simultaneously. Then,the interlayer insulating film 14 is formed on the whole surface byutilizing chemical vapor deposition (CVD) technique or the like.Thereafter a plurality of openings is formed in a predetermined regionof the N-type regions 12 and 13 through steps of photolithography andetching. These openings are formed in the same step as a contact openingstep related to other semiconductor elements (not shown).

Then, the electrode group G1 having the plural electrodes 15 are formedon the N-type region 12, and the electrode group G2 having the pluralelectrodes 16 are formed on the N-type region 13. These electrodes areformed in the same step as a wiring step related to other semiconductorelements (not shown). If a wiring step includes forming of plugs thatfill the openings and patterning of a wiring layer, the electrode groupsG1 and G2 are formed. However, if patterning of a wiring layer allowssimultaneous filling of openings, a wiring pattern is formedsimultaneously with the electrode groups G1 and G2. In addition, of theelectrode group G2, the electrodes 16 are not formed in a region abovewhich a wiring pattern coupled to the electrode group G1 runs through.Otherwise, a wiring pattern coupled to the electrode group G1 is formedin an upper layer than a layer of a wiring pattern coupled to theelectrode group G2.

The structure and method of the above embodiment form the N-type regions12 and 13 as an island region and an annular region surrounding theisland, respectively. The annular region of the N-type well 10 betweenthe island region (12) and the annular region (13) serves as a resistorR. Thus, discharge channels for charges applied excessively because ofESD or the like evenly exist in the periphery (four regions) of theN-type region 12. According to this, even if the occupation area of awell region is based on a minimum or near design rule, the largereffective width (length) of a resistance element can be ensured thanconventional one. Furthermore, these elements can be formedsimultaneously with a step of forming other elements, which providesadvantages in manufacturing efficiency and manufacturing costs. Thus,the concentration of charges can be prevented with an inexpensiveconfiguration and a high performance resistance element that is lesssubject to damage can be provided. In addition, a resistance element inwhich a pattern is fourfold symmetric about the center of the electrodegroup G1 can be formed. This allows greater flexibility in the couplingstructure of the electrode group G2. Specifically, an essential part orall of the electrode group G2 can be utilized by using a multi-layeredwiring pattern or the like.

FIG. 3 is a plan view showing a structure that further includes a wiringpattern for incorporating the structure of FIG. 1 as a resistanceelement into a semiconductor integrated circuit. Also, FIGS. 4A and 4Bshow input-output systems around IC chips and are circuit diagramsincluding a protective resistance element.

Referring to FIG. 3, a wiring pattern 18 is coupled to the pluralelectrodes 15 on the N-type region 12. A wiring pattern 19 is coupled tothe plural electrodes 16 arranged in one of four-divided regions on theN-type region 13. The wiring patterns 18 and 19 may be formedsimultaneously with a step of forming the electrodes 15 and 16. In thisforming, the electrodes 16 (electrode group G2 shown with a dash line)are not formed in a region above which at least the wiring pattern 18coupled to the electrode group G1 runs through. In addition, the wiringpatterns 18 and 19 need not necessarily be formed of the same layer.Specifically, the wiring pattern 18 coupled to the electrode group G1 isformed in an upper layer than a layer of the wiring pattern 19 coupledto the electrode group G2. That is, stacking electrode groups in accordwith wiring layers allows a structure having a pattern made up ofdifferent wiring layers.

Referring to FIG. 4A, one of signal lines in a semiconductor chip isextended from a pad PAD via a resistance element R1 for protection to abuffer BF1 so as to be introduced into an internal circuit. The bufferBF1 is an input circuit, output circuit or input-output circuit forsignals. The use of the structure shown in FIG. 3 as the resistanceelement R1 for protection permits the provision of a circuit having aninexpensive and high performance protective resistance element havinghigh reliability.

Referring to FIG. 4B, one of signal lines in a semiconductor chip isextended from the pad PAD via resistance elements R21 and R22 forprotection to a buffer BF2 so as to be introduced into an internalcircuit. The buffer BF2 is an input circuit, output circuit orinput-output circuit for signals. Since the size of the buffer BF2 issmall and therefore is sensitive to electrostatic damage, an ESDprotective circuit is provided between a node between the resistanceelements R21 and R22, and a ground potential GND. The use of thestructure shown in FIG. 3 as the resistance elements R21 and R22 forprotection permits the provision of a circuit having an inexpensive andhigh performance protective resistance element having high reliability.

FIGS. 5A and 5B are plan views showing structures according tomodifications of the first embodiment. Explanation will be made withusing the same numerals as those in FIG. 3.

Of the electrode group G1 on the N-type region 12, the electrodes on theperipheral part of the N-type region 12 actually serve as electrodes forresistance elements. Therefore, referring to FIG. 5A, the electrodes 15are not provided in a center region A1 but provided in the peripherythereof in two rows. Also, referring to FIG. 5 b, the electrodes 15 arenot provided in a center region A2 but provided in the periphery thereofin one row.

As above, the electrode group G1 on the N-type region 12 need notnecessarily be distributed in the whole region from the center to apredetermined region. It is essential for the electrode group G1 to havethe electrodes 15 that are arranged in a predetermined number at leastalong the four sides of the N-type region 12. Furthermore, the oppositedistance D1 between the four sides of the N-type regions 12 and 13 is,at largest, smaller than the opposite distance D2 between the sides ofthe N-type regions 12 and 13 at four corner regions. In addition,preferably, the electrode group G2 on the N-type region 13 are arrangedin a predetermined number so that the electrodes of the electrode groupG2 one-to-one face electrodes arranged in a predetermined number at thefront rows of the electrode group G1. In other words, both ends of aresistor are made up of one-to-one correspondences between apredetermined number of electrodes and therefore regions preferentiallyserving as a resistor are established. This allows a structure that iseasier to be designed as a resistance element.

FIG. 6 is a plan view showing an essential part of a semiconductordevice according to a second embodiment of the present invention. FIG. 7is a sectional view along line F7-F7 in FIG. 6. The same numerals asthose in FIGS. 1 and 2 are given to the same elements as those in thefirst embodiment.

The second embodiment is different from the first embodiment in that astep of siliciding the N-type regions 12 and 13 is added and a silicidemetal layer 21 is provided in a predetermined region. Otherconfigurations are the same as those of the first embodiment andtherefore will not be explained. The silicide metal layer 21 is disposedon the N-type regions 12 and 13 except for predetermined regionsadjacent to the insulating film 11 for isolation. The reason for this isthat regions free of a silicide metal layer are preferably formed in end(edge) parts of regions serving as a resistor in order to avoid theconcentration of charges. Ideally, the device has a fourfold symmetricpattern about the center of the N-type region 12, and the N-type well 10between the N-type regions 12 and 13 serves as a resistor.

A suicide protect region PROT for achieving a structure to avoid theconcentration of charges is illustrated in the drawing. The silicideprotect region PROT is an insulating film provided in order to preventthe silicidation of the N-type regions 12 and 13. If the disposition ofthe silicide protect region PROT involves some misalignment, the sameoffset of a region in which the silicide metal layer 21 is formed iscaused in the N-type regions 12 and 13 equally. This can hold the totalbalance between regions 12 s and 13 s that have the silicide metal layer21 and therefore have low resistivity.

A method for manufacturing a resistance element shown as a structure inFIGS. 6 and 7 is as follows. The insulating film 11 for isolation thatis at least annular is formed on the N-type well 10. The insulating film11 for isolation is formed so that the inner circumference thereof hasan octagon shape having at least longitudinal four sides while the outercircumference thereof has four sides facing the four sides of the innercircumference. The width of the region between the four sides is setsmaller than that at four corner regions (D1<D2).

Subsequently, an N-type impurity is ion-implanted into the center andperipheral parts of the N-type well 10 with using the insulating film 11for isolation as a mask, to form the N-type regions 12 and 13. The kindand concentration of the ion depends on N-type regions of othersemiconductor elements (not shown) that are formed simultaneously. Then,an insulating film is formed by utilizing chemical vapor deposition(CVD) technique or the like so as to be patterned as the silicideprotect region PROT through steps of photolithography and etching. Thesilicide protect region PROT may be made of the same insulating film asinterlayer insulating films, or may be made of another film. At anyrate, the silicide protect region PROT is desirably formed with aforming step (silicide protect step) based on a step of manufacturingother semiconductor elements (not shown).

Subsequently, the interlayer insulating film 14 is formed on the wholesurface by utilizing chemical vapor deposition (CVD) technique or thelike. Thereafter a plurality of openings is formed in a predeterminedregion of the N-type regions 12 and 13 through steps of photolithographyand etching. These openings are formed in the same step as a contactopening step related to other semiconductor elements (not shown).

Then, the electrode group G1 having the plural electrodes 15 are formedon the N-type region 12, and the electrode group G2 having the pluralelectrodes 16 are formed on the N-type region 13. These electrodes areformed in the same step as a wiring step related to other semiconductorelements (not shown). If a wiring step includes forming of plugs thatfill the openings and patterning of a wiring layer, the electrode groupsG1 and G2 are formed. However, if patterning of a wiring layer allowssimultaneous filling of openings, a wiring pattern is formedsimultaneously with the electrode groups G1 and G2. In addition, of theelectrode group G2, the electrodes 16 are not formed in a region abovewhich a wiring pattern coupled to the electrode group G1 runs through.Otherwise, a wiring pattern coupled to the electrode group G1 is formedin an upper layer than a layer of a wiring pattern coupled to theelectrode group G2. A wiring pattern is formed in the same way as, forexample, the wiring patterns 18 and 19, which have been describedreferring to FIG. 3, although the configuration including the wiringpattern is not illustrated.

The structure and method according to the above embodiment allows thesame advantageous effects as those of the first embodiment.Specifically, the annular region of the N-type well 10 between theisland N-type region 12 and the annular N-type region 13 serves as aresistor R. Thus, discharge channels for charges applied excessivelybecause of ESD or the like evenly exist in the periphery (four regions)of the N-type region 12. Also, regions free of the silicide metal layer21 are formed in end (edge) parts of regions serving as the resistor Rin order to avoid the concentration of charges. According to this, evenif the occupation area of a well region is based on a minimum or neardesign rule, the larger effective width (length) of a resistance elementcan be ensured than conventional one. Furthermore, these elements can beformed simultaneously with a step of forming other elements, whichprovides advantages in manufacturing efficiency and manufacturing costs.Thus, the concentration of charges can be prevented with an inexpensiveconfiguration, and a high performance resistance element that is lesssubject to damage can be provided. In addition, a resistance element inwhich a pattern is fourfold symmetric about the center of the electrodegroup G1 can be formed. This allows greater flexibility in the couplingstructure of the electrode group G2. Specifically, an essential part orall of the electrode group G2 can be utilized by using a multi-layeredwiring pattern or the like.

There is sufficient possibility that the above second embodiment alsoadopts the structure according to modifications like that shown in FIGS.5A and 5B. The same advantageous effects can be expected. In addition,if the above configuration is adopted as a resistance element forprotection that is provided upstream of a circuit in an input-outputsystem around an IC chip, a circuit including inexpensive and highperformance protective resistance element having high reliability can beprovided.

Also, the present invention is not limited to the embodiments in which awell resistor having the N-type well (10) on a semiconductor substrateas a base is shown. A well resistor having a P-type well as a base maybe formed. Moreover, a substrate on which a well is to be formed may bea silicon-on-insulator (SOI) substrate.

As described above, the present invention can provide a resistanceelement employing anti-electrostatic measures that are sufficientlyimproved even when the occupation area of a well resistor is small.Specifically, a well resistor is achieved by utilizing an annular regionbetween an island conductive coupling region and annular conductivecoupling region. This configuration can provide a semiconductor devicehaving an inexpensive and high performance resistance element that canensure, within a more reduced area, a large area for discharging excesscharges due to ESD or the like, and a method for manufacturing thesemiconductor device.

1. A semiconductor device comprising: a semiconductor base of a firstconductivity type; a first conductive coupling region of the firstconductivity type provided on the semiconductor base; a secondconductive coupling region of the first conductivity type provided onthe semiconductor base so as to surround the first conductive couplingregion; a first electrode group having a plurality of electrodes that isprovided on the first conductive coupling region; and a second electrodegroup having a plurality of electrodes that is provided on the secondconductive coupling region.
 2. The semiconductor device according toclaim 1, wherein the semiconductor base is one well region provided on asemiconductor substrate, and the semiconductor base between the firstconductive coupling region and the second conductive coupling regionfunctions as a resistor.
 3. The semiconductor device according to claim1, wherein the semiconductor base is one well region provided on asemiconductor substrate, and has a pattern that is at least fourfoldsymmetric about a center of the first conductive coupling region, thesemiconductor base between the first conductive coupling region and thesecond conductive coupling region functioning as a resistor.
 4. Thesemiconductor device according to claim 1, wherein a peripheralelectrode of the first electrode group in a predetermined number isarranged closest to an edge of the first conductive coupling region ineach of four regions, and an electrode of the second electrode group ina predetermined number is arranged in each of four regions so as to facethe peripheral electrode of the first electrode group.
 5. Thesemiconductor device according to claim 1, wherein the first electrodegroup is distributed in a whole region from a center of the firstconductive coupling region to a predetermined region, a peripheralelectrode of the first electrode group in a predetermined number beingarranged closest to an edge of the first conductive coupling region ineach of four regions, and an electrode of the second electrode group ina predetermined number being arranged in each of four regions so as toface at least the peripheral electrode of the first electrode group in apredetermined number.
 6. The semiconductor device according to claim 1,wherein the first conductive coupling region has a planar shape obtainedby removing four corner parts from a quadrangle and having at least foursides, the first electrode group being prepared so that an electrode ina predetermined number is arranged along the four sides, and anelectrode of the second electrode group in a predetermined number beingarranged so as to face at least the electrode of the first electrodegroup in a predetermined number.
 7. The semiconductor device accordingto claim 1, wherein a distance between the first conductive couplingregion and the second conductive coupling region in a region in whichthe first electrode group faces the second electrode group is smallerthan a distance between the first conductive coupling region and thesecond conductive coupling region in other regions.
 8. A semiconductordevice comprising: a semiconductor base of a first conductivity type; afirst insulating film provided on the semiconductor base; a firstconductive coupling region of the first conductivity type in a centerpart and a second conductive coupling region of the first conductivitytype surrounding the first conductive coupling region, the first andsecond conductive coupling regions being isolated from each other by thefirst insulating film; a second insulating film provided on the firstconductive coupling region and the second conductive coupling region; afirst electrode group having a plurality of electrodes that is providedon the first conductive coupling region via a plurality of openings inthe second insulating film; a second electrode group having a pluralityof electrodes that is provided on the second conductive coupling regionvia a plurality of openings in the second insulating film; a firstwiring pattern coupled to a plurality of predetermined electrodes of thefirst electrode group; and a second wiring pattern coupled to aplurality of predetermined electrodes of the second electrode group. 9.The semiconductor device according to claim 8, wherein a silicide metallayer is formed in the first conductive coupling region and the secondconductive coupling region except for a predetermined region adjacent tothe first insulating film.
 10. The semiconductor device according toclaim 8, wherein the semiconductor base is one well region provided on asemiconductor substrate, and the semiconductor base between the firstconductive coupling region and the second conductive coupling regionfunctions as a resistor.
 11. The semiconductor device according to claim8, wherein the semiconductor base is one well region provided on asemiconductor substrate, and has a pattern that is at least fourfoldsymmetric about a center of the first conductive coupling region, thesemiconductor base between the first conductive coupling region and thesecond conductive coupling region functioning as a resistor.
 12. Thesemiconductor device according to claim 8, wherein a peripheralelectrode of the first electrode group in a predetermined number isarranged closest to an edge of the first conductive coupling region ineach of four regions, and an electrode of the second electrode group ina predetermined number is arranged in each of four regions so as to facethe peripheral electrode of the first electrode group.
 13. Thesemiconductor device according to claim 8, wherein the first electrodegroup is distributed in a whole region from a center of the firstconductive coupling region to a predetermined region, a peripheralelectrode of the first electrode group in a predetermined number beingarranged closest to an edge of the first conductive coupling region ineach of four regions, and an electrode of the second electrode group ina predetermined number being arranged in each of four regions so as toface at least the peripheral electrode of the first electrode group in apredetermined number.
 14. The semiconductor device according to claim 8,wherein the first conductive coupling region has a planar shape obtainedby removing four corner parts from a quadrangle and having at least foursides, the first electrode group being prepared so that an electrode ina predetermined number is arranged along the four sides, and anelectrode of the second electrode group in a predetermined number beingarranged so as to face at least the electrode of the first electrodegroup in a predetermined number.
 15. The semiconductor device accordingto claim 8, wherein a distance between the first conductive couplingregion and the second conductive coupling region in a region in whichthe first electrode group faces the second electrode group is smallerthan a distance between the first conductive coupling region and thesecond conductive coupling region in other regions.
 16. A method formanufacturing a semiconductor device, comprising: forming an annularfirst insulating film on a semiconductor base; forming, with using thefirst insulating film as a mask, a first conductive coupling region of afirst conductivity type in a center part of the semiconductor base and asecond conductive coupling region of the first conductivity type in aperiphery of the first conductive coupling region; forming a secondinsulating film on the first conductive coupling region and the secondconductive coupling region; and forming a first electrode group and asecond electrode group that have a plurality of electrodes on the firstconductive coupling region and the second conductive coupling region,respectively, via a plurality of openings in the second insulating film.17. The method for manufacturing a semiconductor device according toclaim 16, further comprising forming a first wiring pattern coupled to aplurality of predetermined electrodes of the first electrode group and asecond wiring pattern coupled to a plurality of predetermined electrodesof the second electrode group.
 18. The method for manufacturing asemiconductor device according to claim 16, wherein the semiconductorbase is one well region provided on a semiconductor substrate, and formsa resistor, between the first conductive coupling region and the secondconductive coupling region, that is at least fourfold symmetric about acenter of the first conductive coupling region.
 19. The method formanufacturing a semiconductor device according to claim 16, wherein aninner circumference of the first insulating film has an octagon shapethat has at least longitudinal four sides, and an outer circumferenceforms regions of four sides facing the four sides, a width between theinner and outer circumferences in the regions of four sides beingsmaller than a width between the inner and outer circumferences in fourcorner regions.
 20. The method for manufacturing a semiconductor deviceaccording to claim 16, further comprising, prior to the step of formingthe second insulating film: forming a protective layer for preventingsilicidation that covers a predetermined region, of the first conductivecoupling region and the second conductive coupling region, adjacent toat least the first insulating film; and forming a silicide metal layeron the first conductive coupling region and the second conductivecoupling region except for the predetermined region.